Cant get notification

I created a doc field with a specif date (for example end of contract 05-04-2019)
I want to get a notification before this date by 30 days

I’ve done this code ex: “mchStaff”: “managestaff.notifications.get_expired_contract”,
and get no of notification only and no data.
on the other hand ;when i put another condition ex:“mchStaff”: {“no_of_renewal”:“3”}
i get the no of notifications and the data that has the condition
any one can help??